The Upper East Side is silly over Centolire, Pino Luongo’s love song to Italian-American immigrant cooking. Its kitchen shames anything nearby. Its saffron-crusted cioppino, crab-flavored seafood stew, bests all previous cioppinos. So why does the place act downtown-ditzoid?

Upon this land of the two-nanny household, Centolire inflicts a “concept” menu and confused, club-land service. With its greeters on the ground floor but its main dining room upstairs, Centolire has yet to devise a means – a telephone, say – for the two levels to communicate. “I’m all alone tonight,” the hostess says, explaining why it takes forever to seat you.

Centolire is cannily attuned to its environs. The sprawling second floor, with canopied windows overlooking the avenue, kitchen behind frosted glass and long, striped banquettes, has the air of a pre-war co-op sitting room into which a mammoth mortadella-slicing machine somehow wandered.

The meandering mood rules the staff, too. One night, entrees go AWOL. The waitress reports on our runway position: “There are two tables ahead of you.”

Another night, our long-reserved table is not ready for 35 minutes. Dinner is a struggle – for menus, for bread, for sorbet that arrives 20 minutes after it’s ordered, in the wrong flavor. Only the check – $350 for four, with one bottle of ordinary Chianti – arrives promptly.

Executive chef Joseph Marchisotta’s menu is split into fuzzy categories – “Old World” and “New World.” It promises “updated versions of Italian-American cuisine, as well as new creations destined to become classics.”

It isn’t always clear which is which. To muddle things further, Marchisotta also draws on the familiar, Tuscan-influenced Luongo play list, with proven pasta favorites from Le Madri and Coco Pazzo, like fresh gemelli ($16) with pesto, pine nuts, garlic and olive oil.

What’s more confusing is that in either category, some dishes boldly proclaim their garlic-steeped heritage, while others shrink from it. Fabulous cioppino ($29) – seafood stew with saffron crosta di pane – is served as a pot pie, with a noble, golden-brown crust that the waiter deftly slices open. Beneath simmers a bracing brew of tomato, olive oil and crab, crowded with pristine bass and succulent shellfish.

But another theoretical “classic,” spaghetti chitarra with meatballs ($16), seems a study in Italian-American self-negation, in need of Dr. Melfi’s attention. The flat spaghetti, shaped to bear sauce, bears none. Tiny parmesan- and parsley-filled meatballs stand sheepishly to the side.

Timidity knocks the stuffing out of timpano ($22 for two), the southern Italian country “drum” pie made famous in the movie “Big Night,” made with pasta, meatballs, eggplant, sausage and mozzarella. Overbaked and underseasoned, it poses no threat to the most delicate system.

Fish entrees off the “contemporary” list are as strongly seasoned as some other dishes are not – like grilled tuna ($26) happily Luongo-ized with capers, anchovies, tomatoes and chickpeas. Parchment-baked Chilean bass ($26), with eggplant, mint, rosemary, olive and tomato, emerged from the unwrapping by the waiter with an ethereally delicate texture.

Sparkling desserts like Sicilian ricotta semifreddo ($14) send you out happy. Skip the elevator and take the stairs for a display of antique cooking implements. Among them are wooden rolling pins – just the thing to club Centolire’s crew into shape.